Modern aircraft, including fixed-wing aircraft and rotary-wing aircraft, employ a variety of flight control surfaces, such as ailerons, elevators, rudders, flaps, slats, spoilers, air brakes and the like. By manipulating one or more flight control surfaces, a pilot may control the lift generated by the aircraft, such as during takeoff, climbing, descending and landing, as well as the aircraft's orientation about its pitch, roll and yaw axes. Therefore, effective flight control requires effective monitoring and control of the aircraft's flight control surfaces.
For example, the leading edge of a fixed-wing aircraft typically includes slats that, when actuated, alter the aerodynamic shape of the wing. At cruise, the slats are maintained in a retracted position. However, during takeoff, climbing, descending or landing, the slats may be extended, either partially or fully, thereby effectively increasing the chord length of the wing and augmenting lift. Therefore, the lift generated by the wings of the aircraft is highly dependent upon the position (e.g., retracted; partially extended; fully extended) of the slats vis-à-vis the body of the wing.
Typically, each slat is connected to the body of the associated wing by two or more tracks. Each track is typically mounted on guide rollers and typically includes a rack that is engaged with a rotatable pinion. Therefore, actuation of such a slat is effected by rotation of the pinion, which causes the track to move along a track path, which in turn moves the slat between the retracted position, a partially extended position and the fully extended position.
Slat actuation is often monitored to identify a skew or a loss. A skew occurs when one track associated with a slat has asynchronously moved with respect to one or more other tracks associated with that slat. A loss occurs when one or more tracks associated with a slat fails to extend or retract. Unfortunately, the systems presently used to monitor slat actuation are complex (expensive) and heavy.
Accordingly, those skilled in the art continue with research and development efforts in the field of aircraft flight control surface actuation monitoring.